CVE-2020-24355 json
Zyxel VMG5313-B30B router on firmware 5.13(ABCJ.6)b3_1127, and possibly older versions of firmware are affected by insecure permissions whi…
published 2020-09-02 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-17089
- cvss
- 9.8
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 2.2%
- EPSS 2.2% chance of exploitation in 30 days, percentile 82%
- public exploits
- 0
- none known
Summary
Zyxel VMG5313-B30B router on firmware 5.13(ABCJ.6)b3_1127, and possibly older versions of firmware are affected by insecure permissions which allows regular and other users to create new users with elevated privileges. This is done by changing "FirstIndex" field in JSON that is POST-ed during account creation. Similar may also be possible with account deletion.
Exploit prediction
2.18% chance of exploitation in the next 30 days, higher than 82% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- blog.somegeneric.ninja https://blog.somegeneric.ninja/Zyxel_VMG5153_B30B referenced PoC, tagged "exploit" by a source, unverified
- blog.somegeneric.ninja https://blog.somegeneric.ninja/Zyxel_VMG5153_B30B_part2 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVD | 2.0 | 10.0 | AV:N/AC:L/Au:N/C:C/I:C/A:C |
Classification
- Weakness
-
- CWE-732 Incorrect Permission Assignment for Critical Resource
References
-
blog.somegeneric.ninja
/Zyxel_VMG5153_B30B
exploit, third-party-advisory
-
blog.somegeneric.ninja
/Zyxel_VMG5153_B30B_part2
exploit, third-party-advisory
-
zyxel.com
/support/security_advisories.shtml
vendor-advisory
Sources
- CVE List CVE-2020-24355
- NVD CVE-2020-24355
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.